A long-anticipated Senate debate over the Keystone XL oil pipeline appears imminent, with Sen. John Hoeven saying he intends to offer an amendment to the energy efficiency bill that's next on the floor schedule.

"On Keystone, I'll either offer our amendment or maybe the joint resolution, one of those two," the North Dakota Republican said, adding that the bill managers on both sides of the aisle "were trying to kind of find out what were going to be offered."

Hoeven and Sen. Mary L. Landrieu, D-La., have filed a joint resolution expressing the senses of Congress that the pipeline is in the national interests of the United states. More stringent language would require the administration to approve the controversial pipeline project.

Hoeven largely dismissed the possibility that Democratic leaders opposed to pipeline construction could try to lock the amendment process to steer clear of the Keystone pipeline vote. When the Senate held a non-binding vote in support of the oil pipeline from Canada during this year's budget vote-a-rama, Hoeven's side got a filibuster-proof 62 votes in favor.

"There are going to have to be amendments or they're not going to be able to advance the bill," Hoeven said.

"I'll have a number of amendments, like ... the bill that would allow federal buildings to utilize natural gas," he said. "I've got a couple others."

The Senate is now expected to turn to the energy efficiency legislation crafted by Democratic Sen. Jeanne Shaheen of New Hampshire and Republican Sen. Rob Portman of Ohio.

Shaheen said during a floor speech on Tuesday that she expects a robust debate.

"I appreciate the commitment of our leadership on both sides of the aisle in the Senate to do this. I recognize that this will be the first time a major energy bill has reached the Senate floor since 2007," Shaheen said. "Therefore, it only makes sense for us to have a robust energy debate that allows for amendments from both sides of the aisle to be considered."

The Shaheen-Portman legislation had been in the queue to be the first item up on the Senate floor after August recess until the developments in Syria. Now that the Senate's taking a pause from that debate, there appears to be a window for the energy measure. Energy and Natural Resources ranking member Lisa Murkowski, R-Alaska, said that while it has yet to be finalized, the Senate could turn to the energy efficiency measure on Wednesday afternoon, maybe during the 2 o'clock hour.